Green-blue dye.



'NITED STATES PATENT OFFICE.

VVILHELM HERZBERG AND OSWALDSOHARFENBERG, OF BERLIN, GERMANY, ASSIGNORSTO THE AOTIEN-GESELLSOHAFT FUR ANILIN FABRIKATION,

OF SAME PLACE.

GREEN-BLUE DYE.

SPECIFICATION forming part of Letters Patent No. 647,834, dated April17, 1900.

Application fil d December 22, 1899. Serial No. 741,291. (No specimens.)

To ctZZ whom it may concern:

Be it known that we, WILHELM HERZBERG and OSWALD SCHARFENBERG, ofBerlin, in the Kingdom of Prussia, German Empire, have invented new anduseful Improvements in the Production of Green-Blue Dye; and We dohereby declare that the following is a full, clear, and exactdescription of the invention, which will enable others skilled in the IQart to which it appertains to make and use the same.

This invention relates to the production of a green-blue dyestuffbelonging to the triphenylmethane series and is based on the followingobservations:

- We have made the discovery that orthotolu'idin when subjected to thecondensation With tetraethyldiamidobenzhydrol in the presence of strongsulfuric acid as condens- 2o ing agent yields a product which by itsproperties essentially differs from the leuco base obtained from thesame components when the condensation is performed in diluted acidsolutions. While the last-mentioned leuco compound yields on oxidation ablue-violet coloringmatter, the new leuco compound which we haveprepared is transformed by oxidation into a green-blue dye. According toall observations on this subject hitherto 0 published the condensationsof tetraalkyldiamidobenzhydrols with amido compounds in dilutedsolutions unexceptionally take place in such manner that the OH group ofthe hydrol enters into para position to the amido group; provided thatthis position is free. (Compare German patent (expired) No. 27,032;Nolting, Ber ichte 'der Deutschen Ohcmischen Gesellschafi, XXII, page554.) The leuco base formed in diluted solutions 40 for instance, fromortho-toluidin and tetraethyldiamidobenzhydrol-is therefore representedby the formula:

KL QE Nwg a that is to say, that the OH group has entered into metaposition to the NH group. We have further found that the new leuco baseproduced in the way described can easily be diazotized and by boilingoffthe diazo solution obtained converted with very good yield 7 remarkablepower of dyeing even shades.

To further illustrate our invention, we give the following directions:

1. Production of tetmethyldiamtdodiphe- 3o nyl metaamide paratolylmetha'ne.32.6

kilos of tetraethyldiamidobenzhydrol are dissolved in three hundredkilos of sulfuricacid monohydrate, and into the solution obtained 10.7kilos of ortho-toluidin (respectively 15.6

kilos of ortho-toluidin sulfate) are introduced.

By'allowingthe mixture to stand at a temperature of 20 the'condensationis completed after: twelve hours. The mass is thrown on ice, dilutedwith water, and neutralized by means of sodium carbonate, whereupon the161100 base separates in the form of a whitegray powder. It crystallizesfrom hot alcohol in the form of white leaflets, melting at 95 to 96. Itis slightly soluble in hot alcohol, benzene, and ether. 7 v a 2.Production of tct'raethyldidmidodiphernyZ-meta-owy-parct-tolyl-methane.- A refrigerated solution of sevenkilos of sodium nitrite in sixty liters of water is allowed to runslowly into a solution of 41.5 kilos of the above-described leuco basein three hundred liters of-water and sixty kilos of concentratedsulfuric acid. The solution obtained is heated to 50 to and maintainedat this temperature until the diazo compound is totally decomposed.After refrigeration the oxyleuco base is precipitated in the shape ofgray white flakes by the addition of causticsoda lye or sodiumcarbonate. It crystallizes from ligroin in the form' of hard lustrousprisms, melting at 106 to 107. It is slightly soluble in alcohol andether, and hardly soluble in cold ligroin.

It is dis- 3. Production of-the dyestufi 4l.6 kilos of theabove-described oxyleuco base are dissolved in the cold in one hundredand sixty kilos of sulfuric acid monohydrate and twenty-five kilos ofsulfuric acid containing sixty per cent. S0 The mixture is allowed tostand at about 20 until a sample dissolves completely in sodiumcarbonate. 7 The reaction product is then thrown on water and ice,

and the free sulfuric acid is for its greatest part neutralized by meansof lime. The acid solution'is separated from the calcium sulfate byfiltration and entirely neutralized with carbonate of soda. From thesolution thus obtained the sodium salt of the leucosulfo-acid may beprecipitated in the shape of awhite powder by addition of common salt.It is, however, not necessary to isolate this sodiumsalt, the oxidationproduct being as Well obtained from, the leuco solution directly byoxidation. The free leucosulfoacid is obtained in the shape of whiteflakes by adding to an aqueous solution of its sodium salt thetheoretically-required quantity of acetic or mineral acid. Itdissolvesin an excess of these acids. From diluted solutions it crystallizes inalmost colorless needles.

The sulfo-acid forms a calcium salt which is almost insoluble in water.i The oxyleucosnlfonic acid thus produced is converted into thecorresponding dyestufi by treatment with an oxidizing agent, asillustrated by the following example: 51.9 kilos of the sodium salt ofthe oxyleuco-sulfonic acid are dissolved into five hundred liters ofwater, and the theoretical quantity of sulfuric acid and peroxid of leadare added thereto.v After filtering off the sulfate of lead the newdyestuff is precipitated from the solution obtained by means of commonsalt. The same dyestuff is obtained by first oxidizing the oxyleuco.base preparedas above describedand afterwardsulfonating thecoloring-matter formed by the oxidation. Y

The dyestuif forms small green leaflets of metallic luster, easilysoluble in water with blue coloration andvery soluble in cold al-,

cohol. The blue aqueous solution turns yellow when an excess of mineralacid is added. On diluting this acid solution it assumes a greencoloration, Sodiumcarbonate or ammonia do not effect any change of coloreven when the aqueous solution is. heated with in acid-bath finegreen-blue tints.

Having now described our invention and in what manner the same can beperformed,what we claim as new isi The green-blue dye belonging to thetripheble in water or alcohol with blue coloration, 20 the aqueoussolution of said salt turning yellow on the addition of an excess ofmineral acid and assuming a green coloration when this acid solution isdiluted; the solution remaining unchanged when heated with sodium 2 5carbonate or ammonia, or when treated with caustic-soda lye in the cold,but assuming a red-violet solution when boiled with this latter agent;the new coloring-matter dyeing silk and wool green-blue tints.

In witness whereof we have hereunto signedv our names, this 8th day ofDecember, 1899, in the presence of two subscribing witnesses.

' WILHELM HERZBERG.v

OS WALD SCHARFENBERG. Witnesses:

VV'OLDEMAR HAUPT, HENRY HASPER.

